Soil alkalinity is a major factor that restricts the growth of apple roots. To analyze the response of apple roots to alkali stress, the root structure and endogenous hormones of two apple rootstocks, Malus prunifolia (alkali-tolerant) and Malus hupehensis (alkali-sensitive), were compared. To understand alkali tolerance of M. prunifolia at the molecular level, transcriptome analysis was performed. When plants were cultured in alkaline conditions for 15 d, the root growth of M. hupehensis with weak alkali tolerance decreased significantly. Analysis of endogenous hormone levels showed that the concentrations of indole-3-acetic acid (IAA) and zeatin riboside (ZR) in M. hupehensis under alkali stress were lower than those in the control. However, the trend for IAA and ZR in M. prunifolia was the opposite. The concentration of abscisic acid (ABA) in the roots of the two apple rootstocks under alkali stress increased, but the concentration of ABA in the roots of M. prunifolia was higher than that in M. hupehensis. The expression of IAA-related genes ARF5, GH3.6, SAUR36, and SAUR32 and the Cytokinin (CTK)-related gene IPT5 in M. prunifolia was higher than those in the control, but the expression of these genes in M. hupehensis was lower than those in the control. The expression of ABA-related genes CIPK1 and AHK1 increased in the two apple rootstocks under alkali stress, but the expression of CIPK1 and AHK1 in M. prunifolia was higher than in M. hupehensis. These results demonstrated that under alkali stress, the increase of IAA, ZR, and ABA in roots and the increase of the expression of related genes promoted the growth of roots and improved the alkali tolerance of apple rootstocks.

Biomass yields and concentrations of crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude fiber (CF) were analyzed for five cultivars of summer-sown maize (Zea mays L.) stover grown in field trials at three rates of N fertilization, and sampled immediately after grain harvest. The results revealed differences in yields and concentrations of nutrients according to stalk height and hence harvest portion among the cultivars. N application greatly increased biomass yield and CP, especially in upper stalks and to a lesser extent, EE. Concentrations of NDF and ADF decreased as N rate increased. The results show that stovers from all local popular maize cultivars are suitable as animal fodder and that moderate N application improves feed quality of stover.

Crop production in semiarid regions is always challenging because of the high variability of amount and distribution of precipitation. These regions become more important each year, however, because the rapidly increasing and more prosperous world population seeks greater consumption of animal products (meat, milk and eggs) that requires additional grain to that consumed directly. The dry areas of the developing world where approximately 40% of the world population lives comprise about 40% of the earth’s land area. Crop production, particularly cereal grains, must increase in these areas to meet these growing demands. Grain yield of cereal crops is a function of the amount of water used for evapotranspiration (ET), the portion of ET used for transpiration (T), the units of water as T to produce 1 unit of biomass, and the harvest index (HI). The most important factor is the amount of evapotranspiration not only because it is closely proportional to grain yield, but because it tends to also make the other factors more favorable. Therefore, even small increases in ET can be significant. Strategies for manipulating soil and plant conditions for increasing ET, and how additional ET affects the other factors, are discussed for water deficient areas. The use of crop residues as mulch is highly beneficial but often insufficient in dryland regions or is required for animal feed and fuel. Plastic mulch, mainly restricted to China, has significantly increased grain yields in dryland areas by decreasing evaporation from the soil surface.