The trade-offs between resistance and resilience of forage stay robust with varied growth potentials under different soil water and salt stress

Water shortage and soil salinization are important factors restricting crop production worldwide. To conduct accurate yield prediction and reasonable crop layout, more attention should be paid to the performances of crop resistance and resilience under water and salt stress and their trade-off relationships. Here, we set different water (full irrigation, W0; moderate deficit irrigation, W1; and severe deficit irrigation, W2) and salt (S0, S1, S2, S3, S4, S5, and S6, representing 0 parts per thousand, 1 parts per thousand, 2 parts per thousand, 3 parts per thousand, 4 parts per thousand, 5 parts per thousand, and 6 parts per thousand salt in soil) treatments. Together with relevant studies, we analysed the performances of forage resistance (Rt) and resilience (Rs) and their relationships under varied water and salt stress. The results indicated that logarithmic Rt (1g(Rt), the same as 1g(Rs)) and the distribution of 1g(Rs) were affected by water and salt stress, however, the relationships of 1g(Rs)-1g(Rt) stayed stable with the constant slopes (k) and declined intercepts (m) as stress intensified. The physiological mechanisms and trade-offs for fixed species remained robust while the growth potentials varied under stress, which were closely related to stomatal regulations. Forage with larger vertical bar k vertical bar was suitable for fully irrigated regions to achieve higher yields, while regions with detrimental water and salt conditions should select culrivars with smaller vertical bar k vertical bar to ensure production. This study laid the groundwork for the estimation of the perennial forage adaptation and stability, and the method of long-term yield prediction and cultivar management under soil water and salt stress.